Recent years have witnessed the rapid development of deformable electronic devices, which are emerging as an attractive and promising new technology. Such electronics can be incorporated into wearable devices, such as flexible displays, stretchable circuits, hemispherical electronic eyes, and epidermal devices, to name a few. With deformable electronics, devices can be made to fit into a variety of physical spaces without the standard geometric constraints of non-deformable electronic devices. Indeed, such devices may be developed on the nano-, micro-, centi-, or meter level scale for various applications.
Many methods have been utilized to form deformable electronic devices and there are generally two conventional approaches. The first approach is to use organic materials that are intrinsically stretchable to form the electronic devices; however, such organic materials are undesirable for use in high-performance electronics because they have low electrical mobility (i.e., ability for charged particles to move through a medium in response to an electric field). The second approach utilizes an “island-interconnect” structure where multiple inorganic electronic devices are each placed on a rigid island (e.g., substrate) and electrically connected by interconnects that are stretchable, thus making the entire island-interconnect system stretchable. The island-interconnect structures are typically supported by elastomeric substrates, and recent developments in foldable electronics utilize the concept of paper folding (i.e., origami) to increase the flexibility and deformability of the resulting structures. Indeed, one major objective is to improve the flexibility and deformability of stretchable electronic devices to allow them to be used in an even wider variety of applications than was previously possible. With the island-interconnect method, known interconnects are patterned to form a serpentine shape or a semi-similar serpentine shape to improve deformability. The serpentine-based design utilizes the concept of kirigami (i.e., paper-cutting) to make non-straight lines from a two-dimensional plane, such that in-plane stretching is compensated by out-of-plane deformation. However, even the serpentine-based design is limited in its stretchability capacity.
Accordingly, additional methods of forming interconnects that improve stretchability are desired, such that electronic devices with wide functionality and improved portability may be developed.